<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>HELLO WORLD</title>
  <script src="vue.js"></script>
</head>
<body>
    <div id="app">{{content}}</div>
    <script>
          var app=new Vue({
            el:'#app',
            data:{
                content:'hello world'
            }
          });
          setTimeout(function(){
              app.$data.content='再见'
          },2000)
    </script>
</body>
</html>
